Hi Pam j
This is what the government says:
Vehicle tax exemption
You can get a vehicle tax exemption for one vehicle, if you’re eligible.
The vehicle must be registered in the disabled person’s name or their nominated driver’s name.
The vehicle must be used for a disabled person’s personal needs. It cannot be used by the nominated driver for their own personal use.
www.gov.uk/financial-help-disabled/vehicles-and-transport BIS